1. Field of the Invention
This disclosure relates to the field of rotary presses. In particular, to the conversion or retrofitting of existing rotary presses to allow for printing a different number of sheets per rotation than the press was originally designed to print, a folder to operate on such a printing, presslines utilizing such components, and methods of operating such presses, folders, and presslines to produce a differently sized end-product.
2. Description of the Related Art
The adage that time is money is certainly true in the newspaper or publication printing industry. The faster that printing presses can generate a final product, the fewer manhours and resources (e.g., electricity) are required to generate that product; such resource conservation may increase net revenue and make the publication more profitable. Increasing the speed of production also means that fewer press units are required to generate a publication within the generally fixed period of time between when a newspaper is ready for print, and the printing is completed and the newspaper is ready to deliver, decreasing the amount of capital investment and maintenance required.
However, the rate of operation of a printing press is limited by its structural capacity for speed. The large mechanical components of a printing press may not last as long, may be more prone to being damaged, and may be more dangerous to operate, if they are pushed to operate at a speed that is too high. Specifically in a rotary press, the speed of printing has previously been dictated by the rotational speed of the plate and blanket cylinders which are designed to operate at a defined maximum speed.
Another problem in the newspaper or publication printing industry is the bulky and unwieldy size of many larger publications. As the world has become more mobile, and readers utilize the publication in new places, large newspaper pages may be considered difficult to manipulate, particularly for readers in confined spaces such as public transportation, crowded coffeeshops, airplanes, aerobic machines at a fitness center, or the like. As opposed to magazines which are quite compact, newspapers often have large pages not well suited to such uses as the pages will flop around, be unsupported, and be difficult to hold in a viewable position. Even readers without space restrictions may prefer a more compact newspaper simply because it can be easier to handle. It is therefore desirable to rebalance or redesign newspaper sizes to generate a more user-friendly, and therefore more desirable, final product. One manner of doing so may be to shorten both dimensions of the newspaper to allow for a smaller size to be printed while still maintaining familiar size ratios.
While the size of a newspaper can make a newspaper less relevant in today's hectic society, the format and type of presentation can also present problems. Many newspaper presslines were built to print in black and white. Color was, therefore, relatively rare. However, because of changes in technology, consumers are expecting printed matter to be in full color more and more. Since a pressline is a large fixed capital investment, the difficulty of the prior presslines to move toward increased color can present a stumbling block to producing a desirable product without significant additional capital investment.
In addition to operating more quickly and generating a more user-friendly and relevant publication, it is also desirable to conserve paper. In the last few years, paper recycling to reuse discarded paper has become a much more common activity and has become, for many, a big business. Further, as increased political pressure is brought to bear on paper use and paper recycling, paper has generally increased in price to accommodate increased recycling as well as to encourage more efficient use of new and recycled paper.
For a newspaper, the cost of the raw newsprint upon which to print the newspaper can be the most important consideration in whether the newspaper can survive in the marketplace and can be the most significant cost in operating the newspaper. In today's world, a newspaper must compete against radio, television, and the Internet for its share of advertiser's dollars spent towards reporting. As these other technologies are not bound by the use of paper, the cost of raw newsprint can determine whether or not a newspaper can compete and ultimately survive. Newsprint pricing regularly fluctuates on a quarterly basis which can often leave the newspaper uneasy about how the bottom line will look at the end of the year as even a small fluctuation in the last quarter can cancel out the profit margin built into the paper at the beginning of the year.
Most newspaper presslines running today were installed in the 1970's and 1980's before newsprint prices were inflated to the point they are today, when newsprint prices were more stable, and before the need to conserve paper was fully understood. When these presses were installed, the printed size of a page of a newspaper and therefore the size and design of the newspaper presses was generally selected to obtain a particular look of the paper or to allow a particular number of articles of a particular size to appear on various pages, instead of to preserve newsprint. For these reasons, many of these presses utilize newspaper pages which are significantly larger than their more modern counterparts. In the newspaper business, this difference in the newspaper size can result in a massive difference in profitability in the market.
In a newspaper, there are effectively two dimensions of the paper which can be controlled and which determine the amount of paper which is required to print each newspaper. A single sheet of newspaper (the pages which connect in the middle and printed on each side (four pages)) is generally a quadrilateral shape. A newspaper printing press will generally print newspaper pages on a roll of paper (or a paper web as it is often called). This web is printed with multiple sheets across the width of the paper roll (two or more sheets or eight or more pages) with these same pages repeated down the roll of paper. Alternatively, the press may print a first row of sheets, and then a second row below that, before repeating the same pattern of rows. In this way, the newspaper sheets are essentially printed repetitively (serially) on the roll as it is unwound.
This design results because the press generally utilizes a continuously revolving cylinder as the printing surface to print the page. The cylinder has a length corresponding to the width of the paper roll and generally prints one or two pages with each revolution of the cylinder along the length of the roll of paper. Different sheets are printed on a different paper roll (generally on a different press unit) with the newspaper comprising the appropriate sheets from a plurality of press units being properly arranged, cut and folded together. In this way the newspaper is printed as one continuous printing operation without need to pause printing between pages.
As the pages are generally printed upright, to utilize a smaller horizontal dimension and change the paper's size and look, a narrower paper roll is used and the press is generally set up to not utilize the entire width of the printing surface but only that which corresponds to the width of the roll (the ends of the printing cylinder are contacting only empty space as there is no paper to contact). Alternatively, a wider paper roll could be used utilizing more of the length of the printing cylinder and the system could be set up to print more sheets along the width of the paper. For example three narrower sheets (12 pages) may be printed along the width of a slightly wider roll of paper instead of the wider sheets on a narrower paper roll.
Because of the way a rotary press is designed, while this horizontal dimension modification is fairly easy and straightforward and requires no real modification to the printing hardware (since you are effectively “printing air” with the unused capacity), it is difficult to change the height dimension of a newspaper or what is generally called the “cut-off” or “cut-off length.” Because the printing cylinder has a fixed circumference and because the cylinder endlessly rotates providing the repeated pattern of pages, the circumference of the cylinder corresponds to a predetermined number of complete pages. While one can easily configure the cylinder to print blank space at the end of each rotation (e.g., only having ⅞ of the cylinder actually “print”), there is no net paper savings as this unprinted area is not empty, but comprises unused paper which then has to be cut from the resultant pages (taking an additional cutting step) and is waste. Thus, while smaller vertically sized pages can be printed, such printing does not avoid many of the problems of printing the larger pages since there is no paper savings and the step of removing unprinted paper generally complicates and slows the printing process.
In some dynamic presses, the printing cylinder could be modified dynamically so that a continuously changing pattern of repeating pages could be printed to allow for a printing cylinder to print a non-whole number of pages with each revolution, but such a dynamic system is prohibitively expensive in most situations and sufficiently difficult to operate that it is unusable for most newspaper printing operations.
Many newspaper presslines in use today that were installed prior to the interest in paper reduction and speed so they utilize a newspaper page height of 22¾″ or 23 9/16″. Today, new newspaper presslines are installing new presses that print lengths of 21″, 18.5″, or 17″ length to save paper and to print faster. These presses can save 8% to 10% of the newsprint over what an older press uses which is a gigantic savings in cost and materials. They may also produce product more quickly. Further, more modern presses are often set up to provide for increased color use than their prior composition. Therefore, there is a need in the art to have systems and methods for allowing an older press unit utilizing a first cut-off length, to be modified so as to have a new shorter cut-off length without producing wasted paper between individual sheets.
Existing press units are large, heavy, and expensive pieces of machinery. The press units and folder principally comprise a large frame formed out of a material such as cast iron or steel with holes bored therethrough to enable the attachment of the various moveable components in a precise relation. It may not be feasible or desirable to make large-scale adjustments to existing press units or folders, given the cost and precision such adjustments may require. Further, the cost to replace press units and folders with more modern units is often prohibitive, especially for a smaller publication. It is therefore desirable to shorten the page length and increase the rate of production without need for such a large capital expenditure.